Thread pull-off device for sewing machines



Jan. 27, 1953 'KQEMG THREAD PULL-OFF DEVICE FOR'SEWING MACHINES 2SHEETS-SHEET 1 Filed May 12, 1951 INVENTOR. Edward L. [foal/21 39ATTORNEY Jan. 27, 1953 E. ,KOENIG 2,626,580

THREAD PULL-OFF DEVICE FOR SEWING MACHINES v Filed May 12, 19512,-Sl'lEETS-SHEET 2 INVENTOR. Edward Lif'oem 'y ATTORNEY Patented Jan.27, 1953 THREAD PULL-F} DEVICE FOR SEWING MACHINES Edward L. Koenig,Westport, Conn, 'assignor to The Singer Manufacturing Company,Elizabcth,'N. J., a corporation of New Jersey Application May 12, 1951,Serial No. 225,990

6 Claims.

This invention relates to sewing machines and more particularly to athread pull-oh device wh ch op tes during each stitch-forming cycle todraw thread from a source of supply so that it may be made available forstitchin urposes.

One of the bjec s of the presen i ve tio i to provide an improved threadpull-on device which is adjustable so :that various predetermined am ntso thread may e made av l le for stitching purposes.

A other b ct of the p esent inventio is t p o e an mp ov d mpa a i expes ve needle-thread pull-oil device having incorpor ted i t d ust n mea she eby the am n t r ad p ed from th supply 9 b y u eielv n roll d,-

With the above and other objects in view, as will hereinafter appear,the invention comprises the devices, combinations and arrangements ofparts hereinafter set forth and illustrated in the accompanying drawingsof a preferred embodiment of the invention, from which the severalfeatures of the invention and the advantages attained thereby will bereadily understood by those skilled in the art.

In the accompanying drawings, Fig. 1 is a front elevational view of asewing machine embodying the present invention, a portion of thebracketarm of the machine being broken away better to show the mountingof the movable member of the pull-off device.

Fig. 2 is a top plan view of the machine shown in Fig. 1, showing, infull lines, the movable pulloff arm in fully retracted position and, indotted lines, the movable pull-off arm in advanced position.

Fig. 3 represents a vertical transverse sectional view takensubstantially along the line 3-3, Fig. 1. t

Fig. 4 represents an enlarged vertical sectional view takenlongitudinally of the bracket-arm substantially along the line 4-4, Fig.2.

Fig. 5 represents a top plan view of the stav 2' ii, and an overhangingbracket-arm it which terminates in aihollow head l3, A main or bedshaftIA is jcurnaled lengthwise of the bed It and mounted on its rear end is.a combined beltand hand-wheel l5. Journaled .for oscillation in thebracket-arm I2 is .an arm-shaft l6 connected within the standard I l bya driving link IT to the bed-shaft 1.4. At its front end, theoscillatory arm-shaft is connectedby a rock-arm i8 and link l9 :to .aneedleebar 28 journaled for endwise reciprocation .in .the "head 13. Theneedle-bar 28 carries at its lower end an eye-pointed threadcarryingneedle 21, the needle cooperating with a suitable wing-type chain-stitchlooper (not shown) carried in the outer end of the bed-shaft M. The workis adapted to be advanced past the StitChfifOlln lllg devicesbymeans ofa four-motion feeding mechanism located beneath the bed and including afeed-dog which is adapted to operate in the usual four-motion paththrough a slot in the cloth-plate 22. As is customary the work isyieldingly held in contact with the feed-dog by a p-resser-foot 23carried on the lower end of a spring-depressed presser-bar 24 verticallyslidable in the head [3.

The devices for controlling the needle-thread T in its travel from thesource of supply to the needle 2| is best shown in Figs. -1 and 2.Referring to these views, it will be seen that the needlethread T is ledfrom a source of supply through a thread-guide 25, then between thedisks of a tension device 28 of the type substantially like thatdisclosed in the Chason Patent No. 1,862,658, issued June 191 1932. Fromthe tension device 2%, the thread Tpasses through my improvedthreadmeasuring or stitch-bys titch pull-off device later to bedescribed in detail, and thence between the disks or a thread-nippcr -21to a thread-guide 28, a take-up hole 29 in the needle-bar 26, athreadcheck 30' and a thread-guide 3| on a face-plate '32 attached tothe head 13, and then to the eye in the needle 2 l. As is common inmachines of the type disclosed, the thread-nipper 2'! is operated eachstitch-forming cycle to hip or look the thread T, and during the timethat the thread T is so locked the pull-off device is actuated to drawthread from the supply. The closed nipper prevents any thread f-rombeing stolen from the needle.

The StitCh-bYrStitQh pull-01f device comprises a n m l statio er pl e-lke member 83' and a movable thread-engaging member or element '34 formedat its lower end with a conc'aved seat '35 (Fig, 3) shaped to engage thearm-shaft IE and be secured thereto by a screw 38 threaded into thearm-shaft. The movable member 34 projects through a slot 36' in thebracket-arm and its free end is formed with a V-shaped extremity 31which is disposed so that it passes between the spaced limbs 38 and 39provided on the stationary member 33 and engages the needle-thread Textending between the alined thread-guiding eyes 40 and 4| provided inthe spaced limbs 38 and 39. The pull-01f arm 34, in its advanced position of oscillation shown in dotted lines in Fig, 2, forms a bight inthe needle-thread T, the excess thread forming the bight being pulledfrom the supply through the tension device 26. To insure that all thethread forming the bight is pulled from the supply, the pull-off arm 34is timed so that it engages the thread only while the nipper 21 isclosed.

Means are provided for regulating the amount of thread pulled from thesupply and to that end the normally stationary member 33 is supported sothat it can be manually shifted relative to the free end of the pull-offarm 34, thus to change the eifective stroke of the pull-off arm. Asshown in Figs. 4 and 5, the stationary member 33 is provided at one endwith a pivot-pin 42 which projects into a hole drilled in thebracket-arm 12. Intermediate its ends, the stationary member 33 isenlarged and apertured, as at 43, to receive an adjusting eccentric 44preferably integrally formed on the lower end of a regulating knob 45journaled for turning movement on a stud 4S threaded into thebracket-arm I2. To eliminate accidental turning of the regulating knob45, there is provided a compression spring 4'! operating between thehead of the stud 48 and a flange on the regulating knob 45, whereby saidknob is frictionally held in its selected position of adjustment. Tofacilitate the proper adjustment of the thread measuring device, thereis clamped between the bracket-arm I2 and a shoulder on the stud 45(Fig. 4) a pointer or indicator 48 which is disposed to cooperate withsuitable indicia scribed in the skirt portion of the regulating knob 45.

It will be observed in Fig. 6 that the pointer or indicator 48 issecured in place by the shouldered stud 46, adjustment of the indicatorbeing possible by loosening the stud and manually turning the indicator.Also, it will be seen that the eccentric 44 is sized so that it contactssmultaneously the opposite sides of the aperture 43 in the member 33 andthereby maintains the member 33 against sidewise movement. It willfurther be observed that the compression spring 47 functions to depressthe regulating knob 45 into contact with the upper face of the indicator48, thus frictionally to maintain the regulating knob against accidentalturning, and at the same time the shoulder 49 defining the bottom of theskirt of the regulating knob 45 bears lightly against the member 33 andmaintains it in proper assembled relation upon the bracket-arm 12 of themachine.

From the foregoing, it will be understood that the length ofneedle-thread pulled off from the supply at any one stroke of thepull-off member 34 depends upon the position of the thread-guides 43 and4| relative to the pull-off member. It will .be seen in Fig. 2 that byturning the regulating :knob 45 so thatthe member 33 moves clockwiseopposite direction less thread is pulled from the supply.

The needle 2| and the loop-taker (not shown) form the stitches in theusual manner and the needle-bar take-up thread-eye 23 on its downwardstroke with the needle-bar 25) gives its thread up to the loop-taker. Asthe needle-bar begins its upstroke, the nipper 2! opens and releases thethread made available by the pull-off member 34. The take-up eye 29 alsoascends and thereby, in conjunction with the combined actions of thefeeding mechanism and the looptaker, draws up the stitch. At the sametime that it helps to draw up the stitch, the take-up threadeye 29 alsopulls from the supply side of the nipper the length of thread madeavailable by the pull-off member 34. As the pull-off member and thetake-up thread-eye approach the top of their strokes, the nipper 21closes and thus completes the cycle of the needle-thread controllingmechanism. I

From the above, it is to be understood that a sewing machine having thepresent stitch-bystitch'pull-off device is particularly adapted for theproduction of uniform stitches by virtue of having a manually adjustablemember by means of which the operator may adjust the pull-off action tocompensate for any changes made in the stitch length or requiredtightness of stitch.

Having thus set forth the nature of the inventicn, what I claim hereinis:

1. A thread pull-off device for a sewing machine having a frame and anactuating shaft jcurnaled in said frame, comprising, a normallystationary member adjustably supported on said frame and providingspaced thread-guiding eyes, a movable thread-engaging element secured tosaid actuating shaft and traversing the space between saidthread-guiding eyes to form a bight in the thread and thereby pull alength of thread from a source of supply, and means for moving saidspaced thread-guiding eyes relative to said movable element including amanually turnable regulating knob, and an eccentrically disposed surfaceassociated with said regulating knob and engaging said normallystationary member so that the turning of said knob will effect anadjustment of said normally stationary member.

2. A thread pull-off device for a sewing machine having a frame and anactuating shaft journaled in said frame, comprising, a pivotallysupported member providing spaced thread-guiding eyes, a movablethread-engaging element secured to said actuating shaft and traversingthe space between said thread-guiding eyes to form a bight in the threadand thereby pull a length of thread from its source of supply, and meansfor moving said member about its pivot to shift said thread-guiding eyesrelative to said movable thread-engaging element, said means including aregulating knob mounted for turning movement on said frame, aneccentrically disposed surface formed on said knob and engaging saidpivotally supported member, and yielding means associated with saidregulating knob for precluding accidental turning of said regulatingknob.

3. A thread pull-off device for a sewing machine having a frame and anactuating shaft journaled in said frame, comprising, a member pivotallysupported at one end on said frame and at its other end formed withspaced limbs providing a pair of thread-guiding eyes, a movablethread-engaging element secured to said actuating shaft and traversingthe space between said thread-guiding eyes to form a bight in the 5thread and thereby pull a length of thread from its source of supply,and means for swinging said member about its pivot to shift saidthreadguiding eyes relative to said movable threadengaging element, saidmeans including a turnable regulating knob, an eccentrically disposedsurface formed on said knob and engaging said member intermediate itsends, a stud on which said regulating knob is mounted, and a springacting between said stud and said regulating knob for frictionallylocking said regulating knob against accidental turning.

4. A thread pull-off device for a sewing machine having a frame and anactuating shaft journaled in said frame, comprising, a member pivotallysupported at one end on said frame and at its other end formed withspaced limbs providing a pair of thread-guides, a movablethread-engaging member operatively connected to said actuating shaft andmovable between said thread-guides to form a bight in the thread andthereby pull a length of thread from its source of supply, and means formoving said member about its pivot to shift said thread-guides relativeto said thread-engaging element, said means including a regulating knobhaving a shoulder overlying said member intermediate its ends, aneccentrically disposed surface provided on said regulating knob adjacentsaid shoulder and engaging said member, a stud threaded into said frameand supporting said regulating knob, and a coil spring mounted on saidstud and acting between said stud and said regulating knob yieldingly tomaintain said regulating knob in its selected position of adjustment.

5. A thread pull-off device for a sewing machine having a frame and anactuating shaft journaled in said frame, comprising, a plate-like memberpivotally supported on said frame and provided with spacedthread-guides, a movable thread-engaging member operatively connected tosaid actuating shaft and movable between'said thread-guides to form abight in the thread and thereby pull a length of thread from its sourceof supply, and means for moving said member about its pivot to shiftsaid thread-guides relative to said thread-engaging element, said meansincluding a regulating knob disposed on one side of said plate-likemember and having a shoulder overlying said member and indicia scribedin said knob adjacent said shoulder, an eccentrically disposed surfaceprovided on said regulating knob in position to engage said member, apointer arranged on the other side of said plate-like member anddisposed to cooperate with said indicia, a stud extending through saidknob, plate-like member and pointer and threaded into said frame, and acoil-spring mounted on said stud and disposed frictionally to maintainsaid knob in selected set position.

6. A thread pull-off device for a sewing machine havirig a frame and anactuating shaft journaled in said frame, comprising, a plate-like memberpivotally supported on said frame and provided with an aperture andspaced threadguides, a movable thread-engaging member operativelyconnected to said actuating shaft and movable between said thread-guidesto form a bight in the thread and thereby pull a length of thread fromits source of supply, and means for moving said member about its pivotto shift said thread-guides relative to said thread-engaging element,said means including a regulating knob disposed on one side of saidplate-like member and having indicia provided on said knob, aneccentrically disposed surface provided on said regulating knob andprojecting into and contacting the opposite sides of said aperture insaid member, a pointer arranged on the other side of said plate-likemember and disposed to cooperate with said indicia on said knob, a studextending through said knob, plate-like member and pointer and threadedinto said frame, and a coil-spring mounted on said stud and actingfrictionally to maintain said knob in selected set position.

EDWARD L. KOENIG.

' REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,232,381 Onderdouk July 3, 19172,347,761 Bedard May 2, 1944

